ε-Polylysine (ε-PL) is a cationic antimicrobial agent having strong antimicrobial activity. Because ε-PL is highly effective against a broad spectrum of food pathogens and spoilage organisms, and it has great potential for utilization in food and beverage products. Further, based on absorption, distribution, metabolism, excretion, and toxicity (ADMET) studies, ε-PL has been shown to be safe for human consumption. For this reason, it has been approved as generally recognized as safe (GRAS) within the United States for certain food applications.
Despite its high antimicrobial activity, nontoxicity, water-solubility, and good thermal stability use of ε-PL in foods and beverages (comestibles) is currently limited, because it tends to cause product turbidity and/or to form sediments. For example, the addition of as little as 1 ppm (part per million) ε-PL to a commercial green tea beverage can result in the formation of visible precipitates after a short storage time (24 hours). Therefore, the use of ε-PL as an antimicrobial in comestibles is limited despite its efficacy and safety.
There is thus a need for improvements in the delivery of ε-PL to comestibles. It would be advantageous if such delivery could provide high antimicrobial efficacy, together with one or more of long-term antimicrobial efficacy, good physicochemical stability in a comestible, food or beverage, and good aggregation stability in a comestible.